The present invention relates to milling tools and, more particularly, to milling tools with recessed and non-recessed cutting edges.
In the manufacture of turbine rotors, it is conventional to form grooves using a milling cutter having a plurality of cutting edges defining teeth of increasing size as distance from a top of the cutter increases so that the cutter resembles a “fir tree”. Removal of chips from the groove during the milling operation is important to, among other things, prevent the cutter from becoming jammed. One way of preventing jamming is to remove portions of some cutting edges, such as is shown in JP51128778A, however, this can involve complex machining.
It is desirable to provide a milling cutter for forming grooves in a workpiece that can facilitate removal of chips from the groove during milling. It is particularly desirable to provide such a milling cutter for forming “fir tree” shaped grooves.
In accordance with an aspect of the present invention, a milling tool includes a tool body having a longitudinal axis and a first end, a plurality of flutes provided in the tool body and extending to the first end of the tool body, and a plurality of cutting edges, each cutting edge being associated with a respective one of the plurality of flutes, each cutting edge being substantially identical to each other one of the plurality of cutting edges except that at least one but not all of the cutting edges is a recessed cutting edge and at least one but not all of the cutting edges is a non-recessed cutting edge, each recessed cutting edge beginning at a non-zero distance from the first end of the tool body and each non-recessed cutting edge extending to the first end of the tool body, each land associated with each recessed cutting edge having a substantially planar recess therein extending from the beginning of the recessed cutting edge to the first end of the tool body.